Cover lifting device for an electric furnace



May 12, 1959 B. WRONKA 2,886,313

COVER LIFTING DEVICE FOR AN ELECTRIC FURNACE Filed Feb. 4. 195a l9 fzoINVENTOR.

I Ebaa Wren/fa United States Patent-O Application February-4, 1958,Serial No. 713,254 Claims. (Cl. 268-) This invention relates generallyto electric furnaces, and more particularly, to apparatus forcontrolling the cover of an electric furnace.

Electric furnaces having a fixed tank and a cover that is adapted to belifted before being swung or slid away from the tank for the purpose ofcharging the furnace are well known. For raising or lowering the cover,flexible chains or cables are normally attached at three or four pointsto the cover and carried to a power driven hoisting mechanism over guiderollers, pulleys, or the like, which are fixedly located on a swingingarm that extends over the furnace. Suspension ofthe cover on jflexiblechains or wire ropes, has the disadvantage that during sliding orswinging out, the cover oscillates or pendulat'es. out .of control,making relocating of the cover on the furnace body more difficult.Furthermore, when th'e'heavy cover is suspended on long chains or wireropes, these elements may be unequally stretched, causing the cover toapproach the tankat an inclination. 1

Accordingly, it is an object of this invention to provide cover liftingapparatus that guidesandstabilizes the cover when it is being lifted andremoved from a furnace tank and which provides for the use of relativelyshort flexible hoisting means so as to eliminate the problem of thecover failing to properly register with the furnace.

A'furtherobject is to provide coverlifting apparatus thatisdistinguished by its compactness and which'allows guiding of the coveralong perfectly true vertical lines and which at the same time is sodesigned that it conceals and;

offers protection to the cable means upon which the cover is suspended.

It is a general object of this invention to provide a simple andinexpensive furnace cover lifting apparatus, and more specific objectswill appear from time to time throughout the course of the followingspecification.

In general terms, a preferred embodiment of the invention ischaracterized by a furnace cover over which extends a rigid arm by meansof which the cover can be lifted and swung or slid away from the tank.Attached to the cover is a hollow tubular member which extends throughthe arm in which it is guided by suitable bearings. In its preferredform, the tubular member has a slot through its sidewall for theadmission of the grooved and curved periphery of a pivotally mountedsector. A short piece of wire rope is attached to the sector and extendsalong the groove from which it departs tangentially down the center ofthe tube. The lower end of the wire rope is attached to the cover, andwhen the sector is rocked by means of a pull rod or the like, the wirerope partially wraps onto the sector andhoists the cover upwardly whileit is being guided by several tubular members.

A more detailed description of the invention will now be set forth inconnection with the drawing in which:

Fig. l is an elevational view, partly in section and with parts brokenaway, of an electric furnace embodying the invention.

Referring to the drawing it will be seen that the apparatus comprises aconventional refractory lined stationary furnace shell 1 upon whichrests a convex refractory cover 2 through which electrodes, notv shown,ordinarily pass. The cover 2 is conventional in construction andincludes a metal ring 3 in which the refractory material is set.

The invention contemplates lifting and swinging the cover away fromandback in registry with tank 1. For this purpose there is provided asuitable structure from which cover 2 can be suspended, such as a rigidbeam 4 which extends over the cover and which is adapted to slide orswing in a plane parallel with that of the cover 2, subject to controlof' the furnace operator.

In order 'that'cover 2- will :be prevented from pendulating while movinghorizontally,- there is provided a long rigid tubular. member 5 which isfixedly anchored at its lower end to the metal ring. 3 of cover 2through the agency of a pair of confronting clip angles 6 or any othersuitable socket means. Tubular member 5 may be attached' to clip angles6 by means of a bolt or pin 7. Tubular member 5 acts as a vertical guidefor the cover 2 by virtue of the member extending upwardly and through apair of spaced guide bearings 8 which are carried on arm 4. The. guidebearings may beof the sleeve type as illustrated or other'suitable meansmay be employed, such as roller bearings embracing the member 5 onopposite sidestnot shown). Tubular member 5 is provided with an openingor, slot 9 through-its wall for a purpose which will shortly appear. Itis preferred that member 5 be of square cross section to avoid beingweakened too much by the slot :9. The construction is "not confined tothe use of a tubular'member because for the latter a chan nel-shapedmember may be substituted provided it has a side opening correspondingwith slot 9.

From the-construction thus far described it should be evident that cover2 'willlbe guided in a vertical direction when lifted by reason ofthep'resence of tubular members 5 and it should be understood thatordinarily using three or four; such members 5 and associated elementsis recommended so thatthe cover 2 may be suspended at several pointsfroma pair of arms like that designated 4.

For imparting a lifting force to cover 2 there is provided a rockingsector plate, generally designated by the reference numeral 10, a partof whose periphery 11 is arcuate and grooved edgewise at '12. Sector10is mounted for. rotation through a limited angle on a shaft 13 whichmaybe journalled .on arm '4 by any suitable bearing means. Rocking forceisimpartedt'o sector 10 by-means of a pull rod 14 terminating in aclevis pivotally attached to an extension arm 15 on the sector 10. Theremotely opposite end of rod 14 may be attached to a similar sector 10,not shown, on a diametrically opposite side of cover 2 and synchronizedmovement of sectors may be achieved with a turnbuckle 16. Power meansfor imparting a lifting force to the cover 2 through pull rod 14 are notshown.

A short length of flexible chain or wire rope 17 is connected to sector10 at its upper end by an appropriate wire rope socket 18. The lower endof. the wire rope is attached by means of a socket 19 to an intermediatelink 20 which is also connected to the cover 2 by the same pin 7 thatserves to anchor guide tube 5. It will be observed that wire rope 17extends vertically down through the center of tubular member 5 and liesin the groove 12 along the arcuate periphery of the sector which in turnextends laterally nearly to the center of the tube 5, and that since thewire rope 17 lies tangent to groove 12 during all of its angularpositions, the wire rope will remain centered in tubular member 5,regardless of the elevation of cover 2.

From the construction described it should be evident that cover 2 cannotseriously depart from a true horizontal position when lifted from tank 1because of the former being guided vertically by means of severaltubular members 5 and because changes in the length of the wire ropeorflexible hoisting element 17 as a result of stretching are reduced toinsignificance due to their shortness. Stretching and the likelihood ofthe apparatus getting out of adjustment is further reduced bycontrolling rocking sectors by means of a rigid, unyield ing pull rod.

The apparatus operates as follows: An axial force is exerted toward theright on pull rod 14 so that sector 10 rotates clockwise for liftingcover 2. Upon this event, the short wire rope 17 wraps partially on thearcuate groove 12, thus lifting the cover while tubular guide member 5slides upwardly in its guide bearings 8. Cover 2 is then ready for beingswung away from furnace tank 1 along with arm 4, and the furnace isready for charging or gaining access to its interior. When arm 4 isswung back over furnace tank -1, cover 2 is not able to pendulate byreason of the stability imparted to it by the tubular guide members 5.Likewise, when arm 4 is properly positioned, cover 2 will be at rest andprepared for being lowered into perfect registry with the furnace tank 1by forcing sector 10 counterclockwise until the cover bears on the tank.

Having disclosed a preferred embodiment of the invention, many obviousmodifications will now appear to those skilled in the art. Therefore, itis to be understood that .the specific details of the constructiondisclosedherein are for the purpose of illustration, and not limitation,except as made necessary by the scope of the appended claims.

What is claimed is:

1. In a lifting device for lifting and moving an electric furnace cover,the combination with a furnace cover, of arm means extending over thecover, a rigid elongate member fixed at one end to said cover andslidably engaged with said arm means, rocking means pivotally carried onsaid arm means, flexible hoisting means disposed in substantiallyparallel force transmitting relation with said elongate member andfixedly attached at its opposite ends to said cover and said rockingmeans, said rocking means during rocking motion maintaining theapplication of said (force in said parallel direction and meansconnected with said rocking means for rocking the same to thereby wrap aportion of said flexible means on said rocking means for lifting saidcover under guidance of said elongate member.

2. In a lifting device for lifting and moving an elec tric furnacecover, the combination with a furnace cover, '5

of arm means extending over the cover, an elongate hollow member affixedsubstantially perpendicular on said cover and extending toward said armmeans, guide hearing means mounted on said cover and slidably receivingsaid hollow member therethrough, rocking means pivotally carried on saidarm means, said rocking means including a member having an arcuateportion projecting toward the axis of said hollow member, flexiblehoisting means fixedly attached to said rocking means and said coverwith a part of said flexible means lying on said arcuate portion andanother part projecting axially along the interior of said hollowmember, and means connected with said rocking means for rocking the sameand thereby maintaining a portion of said flexible means in engagementwith said arcuate portion and hoisting said cover under the guidance ofsaid hollow member.

3. The invention set forth in claim 2 wherein said hollow 'member has alongitudinal opening into which the arcuate portion of said rockingmeans projects, the axisof said hollow member being in substantiallytangential relation to said arcuate portion.

4. An electric furnace cover lifting device compris-- ing incombination, a furnace cover, arm means extend-- ing over the cover forsuspending it and moving in unison with it in parallel horizontalplanes, an elongate hollow member fixed at one end to said cover andslidably engagedwith said arm means, said hollow member having a sideopening, a sector means pivotally mounted on said arm means and havingan arcuate portion project ing into said hollow member through its sideopening, flexible hoisting means attached at one end to said coverwithin said hollow member and extending tangentially onto said sector toa point of attachment thereon, and rod means operatively coupled withsaid sector for rotating the same through a limited angle to raise andlower said cover under guidance of said elongate member.

5. Hoisting mechanism for an electric furnace cover comprising incombination, a furnace cover, a slidably guided tubular member attachedto said cover and having a lateral opening, sector means mounted on afixed pivot and having a portion projecting through said lateralopening, a flexible hoisting means attached to said cover within saidtubular member and extending tangentially onto said sector means, androd means operatively attached for pivoting said sector means to raiseand lower said cover through the agency of said flexible hoisting means.

Streit June 9,1925 Palm Sept. 27, 1932

